The present invention relates to a chair, especially an office chair or easy chair.
In EP-PS No. 00 85 670 there is disclosed a chair in which a point of articulation of a backrest carrier to a support block of a base pedestal is disposed outside a line connecting the point of articulation of a seat carrier to the block and the point of articulation of the seat carrier to the backrest carrier. This has the consequence that, during pivotation out of a work position, in which the rearward region of the seat carrier is raised furthest and the backrest carrier with backrest is pivoted furthest forward, into a rest position, in which the rearward region of the seat carrier is pivoted furthest downwardly and the upper region of the backrest carrier furthest rearwardly, the seat carrier must perform a relatively large displacement relative to either the block or the backrest carrier. This requires an unintended rearward redisposition of weight of the user during pivotal movement into the rest position. Consequently a sliding hinge, which forms the forward articulation point between the seat carrier and block, is subjected to a high degree of friction, because this hinge must take up by far the larger part of the weight of the user. Moreover, in some circumstances there is the danger of tipping over. The so-called "shirt pull-out effect", which then arises and is described in EP-PS No. 00 85 670 in relation to FIGS. 1 and 2 thereof and is exerted by the backrest on the back of the user during rearward pivotation, then has to be eliminated by a relatively expensive displacement of the backrest relative to the backrest carrier.
DE-GM No. 77 11 865 there is disclosed a chair which, as in the case of EP-PS No. 00 85 670, provides a synchronously coupled displacement of the seat carrier and backrest carrier, inclusive of force store (gas spring) for resetting into a predetermined limit setting (work position). However, the force store is arranged behind the forwardly directed surface of the backrest in order to improve the aesthetics of the structure. However, this is unsuitable for the preferred purpose of use as an office or easy chair. The arrangement of the gas spring in the backrest requires that this be very thick, but an office or easy chair has only a relatively short backrest with a rod-shaped backrest carrier. Moreover, the angle of engagement of the upper part of the gas spring at the backrest carrier is so small that a disadvantageous force transmission ratio results. Finally, a hinge connection with two articulation points is provided for the connection of the rearward region of the seat carrier with the backrest carrier. This is not only expensive to produce, but also susceptible to faults, and obliges a spacing between the rearward region of the seat carrier and the part of the backrest carrier disposed therebelow, whereby the space required by the seat with seat carrier, backrest carrier and pedestal block, is relatively great in height. Some compensation is provided by redisposition of the gas spring into the backrest. If, however, the gas spring were to be disposed underneath the seat carrier, then it would have to be relatively low and would no longer be laterally covered by the seat carrier, backrest carrier or pedestal block. There is thus the danger of snagging articles of clothing and/or injury to fingers which have access to projecting and moving parts. Finally, such a chair has a relatively bulk appearance.
There is thus scope for improvement of such chairs so that on pivotation of the seat carrier and backrest carrier the deviations, which effect their displacement relative to each other, in the pivot arcs of the carriers relative to a support member are relatively small.